diff --git a/index.js b/index.js
index a0b696d..5e67d9e 100644
--- a/index.js
+++ b/index.js
@@ -108,7 +108,7 @@ import {
 // Feature modules
 import { setupPlotButtons, sendPlotProgression } from './src/systems/features/plotProgression.js';
 import { setupClassicStatsButtons } from './src/systems/features/classicStats.js';
-import { ensureHtmlCleaningRegex } from './src/systems/features/htmlCleaning.js';
+import { ensureHtmlCleaningRegex, detectConflictingRegexScripts } from './src/systems/features/htmlCleaning.js';
 
 // Integration modules
 import {
@@ -419,30 +419,92 @@ async function initUI() {
  */
 jQuery(async () => {
     try {
-        loadSettings();
-        await addExtensionSettings();
-        await initUI();
+        console.log('[RPG Companion] Starting initialization...');
+
+        // Load settings with validation
+        try {
+            loadSettings();
+        } catch (error) {
+            console.error('[RPG Companion] Settings load failed, continuing with defaults:', error);
+        }
+
+        // Add extension settings to Extensions tab
+        try {
+            await addExtensionSettings();
+        } catch (error) {
+            console.error('[RPG Companion] Failed to add extension settings tab:', error);
+            // Don't throw - extension can still work without settings tab
+        }
+
+        // Initialize UI
+        try {
+            await initUI();
+        } catch (error) {
+            console.error('[RPG Companion] UI initialization failed:', error);
+            throw error; // This is critical - can't continue without UI
+        }
 
         // Load chat-specific data for current chat
-        loadChatData();
+        try {
+            loadChatData();
+        } catch (error) {
+            console.error('[RPG Companion] Chat data load failed, using defaults:', error);
+        }
 
         // Import the HTML cleaning regex if needed
-        await ensureHtmlCleaningRegex(st_extension_settings, saveSettingsDebounced);
+        try {
+            await ensureHtmlCleaningRegex(st_extension_settings, saveSettingsDebounced);
+        } catch (error) {
+            console.error('[RPG Companion] HTML regex import failed:', error);
+            // Non-critical - continue without it
+        }
+
+        // Detect conflicting regex scripts from old manual formatters
+        try {
+            const conflicts = detectConflictingRegexScripts(st_extension_settings);
+            if (conflicts.length > 0) {
+                console.warn('[RPG Companion] ⚠️ Detected old manual formatting regex scripts that may conflict:');
+                conflicts.forEach(name => console.warn(`  - ${name}`));
+                console.warn('[RPG Companion] Consider disabling these regexes as the extension now handles formatting automatically.');
+
+                // Show user-friendly warning (non-blocking)
+                toastr.warning(
+                    `Found ${conflicts.length} old RPG formatting regex script(s). These may conflict with the extension. Check console for details.`,
+                    'RPG Companion Warning',
+                    { timeOut: 8000 }
+                );
+            }
+        } catch (error) {
+            console.error('[RPG Companion] Conflict detection failed:', error);
+            // Non-critical - continue anyway
+        }
 
         // Register all event listeners
-        registerAllEvents({
-            [event_types.MESSAGE_SENT]: onMessageSent,
-            [event_types.GENERATION_STARTED]: onGenerationStarted,
-            [event_types.MESSAGE_RECEIVED]: onMessageReceived,
-            [event_types.CHAT_CHANGED]: [onCharacterChanged, updatePersonaAvatar],
-            [event_types.MESSAGE_SWIPED]: onMessageSwiped,
-            [event_types.USER_MESSAGE_RENDERED]: updatePersonaAvatar,
-            [event_types.SETTINGS_UPDATED]: updatePersonaAvatar
-        });
+        try {
+            registerAllEvents({
+                [event_types.MESSAGE_SENT]: onMessageSent,
+                [event_types.GENERATION_STARTED]: onGenerationStarted,
+                [event_types.MESSAGE_RECEIVED]: onMessageReceived,
+                [event_types.CHAT_CHANGED]: [onCharacterChanged, updatePersonaAvatar],
+                [event_types.MESSAGE_SWIPED]: onMessageSwiped,
+                [event_types.USER_MESSAGE_RENDERED]: updatePersonaAvatar,
+                [event_types.SETTINGS_UPDATED]: updatePersonaAvatar
+            });
+        } catch (error) {
+            console.error('[RPG Companion] Event registration failed:', error);
+            throw error; // This is critical - can't continue without events
+        }
 
-        // console.log('[RPG Companion] Extension loaded successfully');
+        console.log('[RPG Companion] ✅ Extension loaded successfully');
     } catch (error) {
-        console.error('[RPG Companion] Failed to initialize:', error);
-        throw error;
+        console.error('[RPG Companion] ❌ Critical initialization failure:', error);
+        console.error('[RPG Companion] Error details:', error.message, error.stack);
+
+        // Show user-friendly error message
+        toastr.error(
+            'RPG Companion failed to initialize. Check console for details. Please try refreshing the page or resetting extension settings.',
+            'RPG Companion Error',
+            { timeOut: 10000 }
+        );
     }
 });
diff --git a/src/core/persistence.js b/src/core/persistence.js
index e143bdd..7db626d 100644
--- a/src/core/persistence.js
+++ b/src/core/persistence.js
@@ -18,26 +18,85 @@ import { migrateInventory } from '../utils/migration.js';
 
 const extensionName = 'third-party/rpg-companion-sillytavern';
 
+/**
+ * Validates extension settings structure
+ * @param {Object} settings - Settings object to validate
+ * @returns {boolean} True if valid, false otherwise
+ */
+function validateSettings(settings) {
+    if (!settings || typeof settings !== 'object') {
+        return false;
+    }
+
+    // Check for required top-level properties
+    if (typeof settings.enabled !== 'boolean' ||
+        typeof settings.autoUpdate !== 'boolean' ||
+        !settings.userStats || typeof settings.userStats !== 'object') {
+        console.warn('[RPG Companion] Settings validation failed: missing required properties');
+        return false;
+    }
+
+    // Validate userStats structure
+    const stats = settings.userStats;
+    if (typeof stats.health !== 'number' ||
+        typeof stats.satiety !== 'number' ||
+        typeof stats.energy !== 'number') {
+        console.warn('[RPG Companion] Settings validation failed: invalid userStats structure');
+        return false;
+    }
+
+    return true;
+}
+
 /**
  * Loads the extension settings from the global settings object.
  * Automatically migrates v1 inventory to v2 format if needed.
  */
 export function loadSettings() {
-    if (power_user.extensions && power_user.extensions[extensionName]) {
-        updateExtensionSettings(power_user.extensions[extensionName]);
-        // console.log('[RPG Companion] Settings loaded:', extensionSettings);
-    } else {
-        // console.log('[RPG Companion] No saved settings found, using defaults');
-    }
-
-    // Migrate inventory if feature flag enabled
-    if (FEATURE_FLAGS.useNewInventory) {
-        const migrationResult = migrateInventory(extensionSettings.userStats.inventory);
-        if (migrationResult.migrated) {
-            console.log(`[RPG Companion] Inventory migrated from ${migrationResult.source} to v2 format`);
-            extensionSettings.userStats.inventory = migrationResult.inventory;
-            saveSettings(); // Persist migrated inventory
+    try {
+        // Validate power_user structure
+        if (!power_user || typeof power_user !== 'object') {
+            console.warn('[RPG Companion] power_user is not available, using default settings');
+            return;
         }
+
+        if (!power_user.extensions) {
+            power_user.extensions = {};
+            console.log('[RPG Companion] Created power_user.extensions object');
+        }
+
+        if (power_user.extensions[extensionName]) {
+            const savedSettings = power_user.extensions[extensionName];
+
+            // Validate loaded settings
+            if (!validateSettings(savedSettings)) {
+                console.warn('[RPG Companion] Loaded settings failed validation, using defaults');
+                console.warn('[RPG Companion] Invalid settings:', savedSettings);
+                // Save valid defaults to replace corrupt data
+                saveSettings();
+                return;
+            }
+
+            updateExtensionSettings(savedSettings);
+            // console.log('[RPG Companion] Settings loaded:', extensionSettings);
+        } else {
+            // console.log('[RPG Companion] No saved settings found, using defaults');
+        }
+
+        // Migrate inventory if feature flag enabled
+        if (FEATURE_FLAGS.useNewInventory) {
+            const migrationResult = migrateInventory(extensionSettings.userStats.inventory);
+            if (migrationResult.migrated) {
+                console.log(`[RPG Companion] Inventory migrated from ${migrationResult.source} to v2 format`);
+                extensionSettings.userStats.inventory = migrationResult.inventory;
+                saveSettings(); // Persist migrated inventory
+            }
+        }
+    } catch (error) {
+        console.error('[RPG Companion] Error loading settings:', error);
+        console.error('[RPG Companion] Error details:', error.message, error.stack);
+        console.warn('[RPG Companion] Using default settings due to load error');
+        // Settings will remain at defaults from state.js
     }
 }
 
diff --git a/src/systems/features/htmlCleaning.js b/src/systems/features/htmlCleaning.js
index 3c1e4b0..8023389 100644
--- a/src/systems/features/htmlCleaning.js
+++ b/src/systems/features/htmlCleaning.js
@@ -3,6 +3,37 @@
  * Automatically imports HTML cleaning regex to strip HTML tags from outgoing prompts
  */
 
+/**
+ * Detects old manual regex formatters that might conflict with the extension
+ * @param {Object} st_extension_settings - SillyTavern extension settings object
+ * @returns {Array<string>} Array of conflicting regex script names
+ */
+export function detectConflictingRegexScripts(st_extension_settings) {
+    const conflictingNames = [
+        'Format User\'s Stats (Only Output)',
+        'Format User\'s Stats (Only Display)',
+        'Format Info Box (Only Output)',
+        'Format Info Box (Only Display)',
+        'Format Character\'s Thoughts (Only Output)',
+        'Format Character\'s Thoughts (Only Display)',
+        'Format Character Thoughts (Only Output)',
+        'Format Character Thoughts (Only Display)'
+    ];
+
+    const existingScripts = st_extension_settings?.regex || [];
+    const conflicts = [];
+
+    for (const script of existingScripts) {
+        if (script && script.scriptName && conflictingNames.some(name =>
+            script.scriptName.toLowerCase().includes(name.toLowerCase())
+        )) {
+            conflicts.push(script.scriptName);
+        }
+    }
+
+    return conflicts;
+}
+
 /**
  * Automatically imports the HTML cleaning regex script if it doesn't already exist.
  * This regex removes HTML tags from outgoing prompts to prevent formatting issues.
@@ -11,10 +42,25 @@
  */
 export async function ensureHtmlCleaningRegex(st_extension_settings, saveSettingsDebounced) {
     try {
+        // Validate extension settings structure
+        if (!st_extension_settings || typeof st_extension_settings !== 'object') {
+            console.warn('[RPG Companion] Invalid extension_settings object, skipping HTML regex import');
+            return;
+        }
+
         // Check if the HTML cleaning regex already exists
         const scriptName = 'Clean HTML (From Outgoing Prompt)';
         const existingScripts = st_extension_settings?.regex || [];
-        const alreadyExists = existingScripts.some(script => script.scriptName === scriptName);
+
+        // Validate regex array
+        if (!Array.isArray(existingScripts)) {
+            console.warn('[RPG Companion] extension_settings.regex is not an array, resetting to empty array');
+            st_extension_settings.regex = [];
+        }
+
+        const alreadyExists = existingScripts.some(script =>
+            script && typeof script === 'object' && script.scriptName === scriptName
+        );
 
         if (alreadyExists) {
             console.log('[RPG Companion] HTML cleaning regex already exists, skipping import');
@@ -55,11 +101,16 @@ export async function ensureHtmlCleaningRegex(st_extension_settings, saveSetting
         st_extension_settings.regex.push(regexScript);
 
         // Save the changes using the already-imported function
-        saveSettingsDebounced();
+        if (typeof saveSettingsDebounced === 'function') {
+            saveSettingsDebounced();
+        } else {
+            console.warn('[RPG Companion] saveSettingsDebounced is not a function, cannot save HTML regex');
+        }
 
         console.log('[RPG Companion] ✅ HTML cleaning regex imported successfully');
     } catch (error) {
         console.error('[RPG Companion] Failed to import HTML cleaning regex:', error);
+        console.error('[RPG Companion] Error details:', error.message, error.stack);
         // Don't throw - this is a nice-to-have feature
     }
 }
diff --git a/style.css b/style.css
index ed880ba..b1732ce 100644
--- a/style.css
+++ b/style.css
@@ -2866,7 +2866,7 @@ body:has(.rpg-panel.rpg-position-left) #sheld {
     background: var(--rpg-highlight, #e94560);
     color: white;
     border: 2px solid var(--rpg-bg, rgba(30, 30, 50, 0.95));
-    font-size: 1.7vw;
+    font-size: clamp(0.9rem, 1rem, 1.1rem);
     line-height: 1;
     cursor: pointer;
     display: flex;
@@ -2894,7 +2894,7 @@ body:has(.rpg-panel.rpg-position-left) #sheld {
     display: flex;
     align-items: center;
     justify-content: center;
-    font-size: 1.85vw;
+    font-size: clamp(1.3rem, 1.4rem, 1.5rem);
     cursor: pointer;
     animation: thoughtIconPulse 2s ease-in-out infinite;
     box-shadow: 0 4px 16px rgba(0, 0, 0, 0.5);
@@ -3016,7 +3016,7 @@ body:has(.rpg-panel.rpg-position-left) #sheld {
 /* Thought content on the right */
 .rpg-thought-content {
     flex: 1;
-    font-size: clamp(0.68vw, 0.7vw, 0.72vw);
+    font-size: clamp(0.85rem, 0.9rem, 0.95rem);
     line-height: 1.5;
     color: var(--rpg-text, #eaeaea);
     font-style: italic;